Typical prior art photographic film processors comprise a plurality of processing tanks, each containing a processing solution for effecting treatment to a photosensitive film which passes through the processing tank. Each of the processing tanks require replenishment solution to be added in order to restore the chemical components of the processing solution and dilute the by-products of the development reaction that occurs within the tank. The addition of the replenishment solution maintains the tank activity at a substantially constant level. The chemical formula of a replenisher is based on the chemical consumption and/or generation that occurs when processing an average film with average exposure, or an average distribution of film types and speed with an average distribution of exposures. The amount of the replenisher is based on the area of the film that has been exposed. In practice, the concentration and rates are often determined for an individual processor by trial and error and through experience.
There are several problems associated with prior art replenishment systems. One problem is that the chemical composition of the replenisher may not be adequate for all film types and mixtures of films. This results in non-standard chemical levels or activity when processing other than the standard film or film mix. Another problem experienced by prior art processors is that the chemical composition of the replenisher may not be adequate for all types or distributions of exposures. The generation or consumption of chemicals from the film will vary depending upon the amount of exposure the film has received. A further problem associated with the replenisher is that the quantity of replenisher is not optimized for all film types and exposures. In addition to supplying of chemical components that are consumed in development, the replenisher is used to flush or dilute the by-products coming from the film. Different film speeds or types can have different generation or consumption terms. Different exposure levels will also change the chemical generation. This is particularly true of standard development by-products such as iodide (measured as KI) and bromide (measured as NaBr) in the developers. Current replenishment systems can not compensate for practical processing occurrences such as portions of film that are either unexposed or totally fogged. The chemical generation for such films will be sufficiently different than that of correctly exposed film. Also, current replenishment system rates are typically based on the surface area of film that has been processed. A predetermined amount of replenisher is used for a set amount of film. The concentration of the individual components in the replenisher are set by the manufacturer of the replenisher. The end user has only limited flexibility in modifying its use. Replenishers that are supplied in more than one part are required to be used in a set ratio.
There has been suggested in the prior art the introduction of replenishment solution to the processing tank based upon the final density of the film that has been processed. The density is measured and a predetermined amount of replenishment solution is supplied to the processing tank. However, these systems, have a single replenisher containing multiple chemical components. The components are simply provided in one predetermined ratio. Therefore, at least one of the components will be added at a rate different than what is necessary for the optimum replenishment of the processing solution.
Applicants have invented an improved method and apparatus for processing the photosensitive material which utilizes a multiple component replenishment system wherein means are provided for measuring a known parameter of the photosensitive material during processing, and based on this information, means for independently supplying the individual components of the multiple chemical components necessary for replenishing the processing solution.